muraii

This plugin does the same thing as the the_author tag, displays the author name, however this one is linked to a hidden div(layer). Once you click on the author name the hidden div will show up together with the author details (taken from author profile page) plus the gravatar photo if the author has one, as well as a link to the author’s BuddyPress profile. If not, the default gravatar photo would be used.
This is a refinement of Igor Penjivrag’s Author Exposed plugin, released in 2008. See http://colorlightstudio.com/2008/03/14/wordpress-plugin-author-exposed/ for that plugin.
This plugin was developed specifically for use with WordPress MU and BuddyPress. It will work with WordPress, but the author link (my main point of interest) won’t be operable. That may change in a future version/adaptation of the plugin.
<ul>
<li>Comes with separate css file for easier modification.</li>
</ul>

BuddyPress Author Exposed

This plugin does the same thing as the the_author tag, displays the author name, however this one is linked to a hidden div(layer).

Valice

Banner alerts are custom alerts to notify your website visitors of promotions, alerts, events, etc. These display at the top of the website until they are dismissed by the visitor. Any new visitor who has not been to the website will see these until they are dismissed.
Banner alerts are configured just like a post or page with support for title, content, and excerpt. The plugin settings allow you to define which parts of the alert to display and whether or not to link to the full post. You can run more than one alert at a time and activate or deactivate as needed.
This plugin is ideal for:
<ul>
<li>Important operational changes</li>
<li>Technical notices</li>
<li>Time-sensitive appeals for donation or action</li>
<li>Terms or agreement changes</li>
<li>Privacy notice acknowledgements</li>
<li>Service outages or maintenance messages</li>
<li>Special offers or promotions</li>
</ul>

Banner Alerts

Provides an easy interface for creating and displaying alerts or notices as a banner on a website

BuddyPress Author Exposed vs Banner Alerts